Ronald Modesitt wrote:
> All,
>
>
>
> I would like to differentiate the function
>
> y(x):={(a*x+b)/(c*x+d)}^7
>
> and limit the expansion so that the result is similar to a manual
> application of the Chain Rule, i.e.
>
> dy/dx = 7{(ax+b)/(cx+d)}^6*{(ad-cb)/(cx+d)^2} (Maxima
> syntax omitted)
>
> or the simplified
>
> dy/dx = 7(ad-cb)(ax+b)^6/(cx+d)^8
>
>
>
> When applying diff(y(x),x) I receive a completely expanded result. I?ve
> tried setting expon:7 but without the desired result.
diff(y(x),x) seems ok to me. But maybe you want factor(diff(y(x),x))?
factor(diff(y(x),x)) -> 7*(a*d-b*c)*(a*x+b)^6/(c*x+d)^8
But note that maxima's answer is correct, even if it's not the form you
wanted. But that's not maxima's fault. :-)
Ray